As an electrophotographic image forming apparatus, there is known a tandem-type color printer that includes a plurality of image carriers corresponding to respective colors of yellow, magenta, cyan, and black.
As such a tandem-type color printer, there is proposed a printer provided with a drum unit including four photosensitive drums that correspond to the respective four colors, bearing members that support the respective photosensitive drums, and inner side plates that position the respective photosensitive drums by integrally supporting the photosensitive drums through the bearing members.